A Javascript Fibonacci (Generator) Function

May 30, 2013

function fibonacci () {
	var f1 = 1;
	fibonacci = function () {
		var f2 = 1;
		fibonacci = function () {
			var f3 = f1 + f2;
			f1 = f2;
			f2 = f3;
			return f3;
		}
		return f2;
	}
	return f1;
}

in ES6(Harmony), the generator keyword: yield will be introduced, a generator function will be like this:

function fibonacci(){
	var fn1 = 1;
	var fn2 = 1;
	while (1){
		var current = fn2;
		fn2 = fn1;
		fn1 = fn1 + current;
		yield current;
	}
}